Current 3GPP standards are lacking in specifications for how a serving Radio Network Controller (RNC) in a Universal Mobile Terrestrial System (UMTS) handles call establishment and post establishment requests during serving RNC Relocation. Section 8.6.2 of 3GPP TS 25.413 version 3.5 (2001–03): UTRAN Iu Interface RANAP Signaling (hereinafter referred to as 25.413) specifies only that if a Radio Access Network Application Part (RANAP) message arrives from the core network (CN), the serving RNC either processes the message as soon as possible or ignores the message. A copy of 25.413 can be obtained via the world wide web at http://www.3gpp.org/ftp/Specs/2001–06/R1999/25_series/. 25.413 is incomplete for both User Equipment (UE) originated and terminated call establishment. If a call establishment request message is processed immediately and an Iu connection is established, resources may be wasted if the connection is relocated (i.e., released) later on. On the other hand, if the message is ignored, and serving RNC Relocation is cancelled later, call blocking may increase.
U.S. Pat. No. 6,225,944 issued to Stephen Hayes on May 1, 2001 describes a method of reporting the location of a MS. However, the patent does not address MS mobility and serving RNC Relocation. U.S. Pat. No. 6,263,203 issued to Alfed Jahn on Jul. 17, 2001 describes a method for seamless handover of a connection from a switch to a MS via two base stations. The patent provides a general relocation mechanism between two base stations, but it does not address the interaction between call connection and serving RNC Relocation. U.S. Pat. No. 6,137,783 issued to Krister Sallberg on Oct. 24, 2000 describes a system and method for reducing the transfer of mobility management information. However, the patent does not address the mobility issue that requires the relocation of the RAN-CN Network (CN) interface. Finally, U.S. Pat. No. 5,953,667 issued to Hanna-Maria Kauppi on Sep. 14, 1999 describes a method to reduce paging time in a cellular network. The patent does not address the handling of call establishment request messages during serving RNC Relocation.
Thus, there is a need for a method of handling call establishment and post establishment requests during location management.